Machinery for making pressware containers typically comprises an optional scoring station, a blanking station and a forming station. In use, one or more paperboard webs is optionally scored in a scoring station and cut into blanks in the blanking station. The blanks (which can comprise a single blank or stack of blanks cut from multiple webs) are then typically directed along an inclined plane to be gravity fed to the forming station. The forming station generally comprises a pressware forming tool which, in turn, comprises a plurality of die pairs. The forming tool is oriented in the cross-direction of the press. Such die pairs generally comprise an upper male portion or punch as well as a lower female portion or die. The female die generally comprises a central knock-out portion mounted on a shaft with a tapered end. The tapered end cooperates with a corresponding taper in a mounting bushing to limit travel of the knockout. After pressing, the pressware is directed by the knockout (such as disclosed in U.S. Pat. No. 6,589,043, which disclosure is incorporated herein in its entirety by this reference) and air assist to a stacking and packaging area. (When a blank fed operation is used, the scoring station and blanking stations are not present.)
Pressware apparatus are expensive and durable equipment. Once purchased, this equipment generally can be used for 10 or 15 or more years before needing replacement. The expense and durability of pressware apparatus make it difficult to obtain efficiencies in the manufacture of pressware. It is generally only possible to find efficiencies in areas peripheral to the manufacture of the pressware e.g., reduction in paperboard weight, coatings etc. Accordingly, conventional methods of improving efficiencies generally result in reduction of the quality of the pressware product formed.
It would be desirable to be able to modify existing pressware apparatus to provide efficiencies in the pressware manufacturing process itself without affecting the quality of the pressware product. The present invention provides for more efficient use of available cross-directional width in a standard-sized forming station by allowing the addition of at least one additional die pair in the pressware forming tool. This has been found to markedly improve the output of a pressware forming apparatus without the drawbacks noted above. Also, the present invention provides components that can be used in conjunction with this improved efficiency pressware apparatus.